Nitriding induction hardening steel and nitriding induction hardening parts

摘要

PROBLEM TO BE SOLVED: To provide a nitrided, induction-hardened component that has good dimensional accuracy and high surface fatigue strength and is excellent in wear resistance, and a steel for nitriding and induction hardening, which serves as a material thereof.SOLUTION: The steel for nitriding and induction hardening comprises, by mass, 0.30% but ≤0.60% C, 0.02-1.90% Si, 0.30-2.00% Mn, 0.50% but ≤1.00% Al, 0.001-0.021% S, 0.001-0.010% N and the balance being Fe and unavoidable impurities, wherein Mn/S is from 70 to 1,500 and Al+Si is ≤2.50%. Preferably, the steel further comprises, by mass, ≤1.60% Cr, and satisfies the relation: 1.9Al+Cr≤2.60%. The steel may comprise one or more elements chosen from Ti, Nb, V, Mo, B, Ni, Cu and Ca. The nitrided, induction-hardened component comprises a base metal having a composition within the range and has a nitrogen concentration of ≥0.4% at a depth of 0.2 mm from its surface.